For me at least, the /goal is a really sick feature and I love the basis of it, of course if you ask claude to make you facebook with no mistakes and have that as a goal, it's not going anywhere...
So the /goal feature is sort of a loop based system, the harness engineering behind it is quite fun, it keeps working towards a goal you give it and it doesn't end after a small while, it goes on until either you or the AI model decides that it's functional and how we want it to be.
In addition to /goal, there's:
/background - An additional feature that let's you put your current terminal run in the background in a way, you can open up 1 central terminal and manage all the running agent's/tasks across different projects or folders and keep it all structured. This is a really nice feature for me as I have about 5 different terminals for 5 completely unrelated projects at the same time. Not sure how knew it is but I found out about it quite recently.